coefficient A[¦kō·ə′fish·ənt ′ā]
A component of magnetic compass deviation of constant value with compass heading, resulting from mistakes in calculations, compass and pelorus misalignment, and unsymmetrical arrangements of horizontal soft iron.
The coefficient of constant compass deviation caused by misplacement of the lubber line of a compass in relation to the longitudinal axis of the carrying aircraft. This misplacement results in a constant error for all headings of the airplane. Coefficient A is the mean value of the deviations on all cardinal and quadrantal headings. Coefficient A = 1/8(Deviation on magnetic North + South + East + West + Northeast + Northwest + Southeast + Southwest).